1. Field of the Invention
This invention relates generally to dishwashers of the household type and more particularly to a spray arm bearing support system for a lower spray arm which incorporates a feed system for an upper level spray system.
2. Description of the Related Art
Nearly all domestic dishwashers include a lower wash arm that rotates about a vertical axis. Most of the larger dishes are carried on a lower rack which rolls on wheels on ledges formed on the sides of the tub and out onto the fold down front door. An upper rack is also provided for smaller articles including cups and glasses, and it is mounted on rollers and tracks to also be moveable in or out of the tub for loading and unloading. It has been found that a single rotary lower wash arm does not always give good washability performance because the spray path can be blocked by dishes on the lower rack and very little water may reach some articles on the upper rack. Therefore, nearly all dishwashers include an upper or second level spray mechanism to provide a spray both upward and downward beneath the upper rack to spray upward directly on the articles in the upper rack and downwardly on to the articles on the lower rack.
Lower spray arms are generally mounted directly above the recirculation pump and receive wash liquid directly therefrom. Different approaches have been taken to rotatably support a lower spray arm and provide a thrust bearing surface. For example, U.S. Pat. Nos. 3,866,837 and 5,427,129 disclose different spray arm bearing support systems.
The upper rack spray system may include a rotating wash arm similar to the main or lower wash arm which may be mounted directly to the upper rack and receive wash liquid through an upper arm feed system. Different approaches have been taken to feed and rotatably support upper spray arms. One approach for an upper arm feed system is to utilize a tower mounted to the lower rack which receives wash liquid from the lower spray arm and has an open upper end such that wash liquid is sprayed through the tower upwardly into a bottom inlet in the upper spray arm for supplying the upper arm with wash liquid. U.S. Pat. No. 5,330,102 discloses a center tower type system for feeding an upper spray arm having a bottom inlet.
Another approach to supplying wash liquid to an upper rack spray system is to feed wash liquid to an upper spray arm through an liquid conduit which is mounted on the exterior of the dishwasher tub. U.S. Pat. Nos. 4,172,463, 4,004,600 and 5,211,190 are all examples of this type of approach. Generally, a discharge outlet from the wash pump is provided which is connected to an liquid conduit which is routed along the exterior of the dishwasher tub. The liquid conduit passes through the tub back into the wash chamber in an area near the upper rack to feed wash liquid to the upper spray arm.
The upper spray arm of a dishwasher may also be fed through the use of an internally disposed supply conduit. In such case, the wash pump of a dishwasher may be provided with a discharge outlet for supplying a conduit which extends along the inside surface of the dishwasher tub to a location near the upper dishwasher rack to feed wash liquid to the upper spray arm. One of the problems with systems that utilize internal conduit systems for supplying wash liquid to the upper spray arm is that the dishwasher wash pumps must be provided with two outletsxe2x80x94a lower spray arm outlet and an upper spray arm outlet.
It can be appreciated from a review of the prior art spray arm systems that there exists a need for simple, low cost and effective spray arm support system which maximizes the dishrack capacity. Moreover, there exists a need for a spray arm system which provides for wash liquid feed to both a lower spray arm and an upper spray arm in a simple, cost effective manner.
By the present invention, there is provided a dishwasher having a tub having a bottom sump and a side wall wherein a first dishware rack is supported within the tub and a second dishware rack is supported within the tub above the first dishware rack. A pump is provided for drawing wash liquid from the sump for pumping wash liquid through a pump outlet. A cap member rotatably connects a first spray arm to the pump outlet such that the first spray arm is rotatably supported above the pump and below the first dishware rack. The cap member is provided with a discharge conduit. A supply line extends from the discharge conduit and is secured to the tub. A second spray arm is supported above the first dishware rack and receives wash liquid through the supply line.
The present invention further provides a dishwashing machine including a tub for receiving articles to be washed and a pump for spraying wash liquid within the tub such that wash liquid is recirculated within the tub. A cap member is arranged in the bottom of the tub for defining a main wash liquid outlet for the pump. A spray arm is disposed within the tub above the cap member. A hub member is attached to the spray arm and extends downwardly from the spray arm. The hub member includes a cylindrical bearing surface. The cap member has an annular bearing surface arranged between the cylindrical bearing surface and the spray arm such that the spray arm is rotatably supported by the cap member. The cap member further has a discharge outlet conduit wherein a portion of the wash liquid supplied to the cap is directed through the discharge outlet away from the main liquid outlet. The discharge outlet fluidly connects to an supply tube for supplying wash liquid to a second spray arm mounted within the tub.